|Publication number||US6997637 B2|
|Application number||US 10/005,820|
|Publication date||Feb 14, 2006|
|Filing date||Dec 4, 2001|
|Priority date||Dec 6, 2000|
|Also published as||US20020085880|
|Publication number||005820, 10005820, US 6997637 B2, US 6997637B2, US-B2-6997637, US6997637 B2, US6997637B2|
|Inventors||William C. Schneider, P. James Locke|
|Original Assignee||The United States Of America As Represented By The National Aeronautics And Space Administration|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (23), Referenced by (2), Classifications (20), Legal Events (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims priority from, and incorporates herein by reference, provisional application No. 60/254,285, entitled “Energy Absorbing System,” filed with the U.S. Patent and Trademark Office on Dec. 6, 2000.
The invention described herein was made by employee(s) of the United States Government and may be manufactured or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
1. Field of the Invention
The present invention relates generally to barrier systems and, more particularly, to deceleration-limiting barrier systems for decelerating moving objects in a controlled manner.
2. Description of the Related Art
Various types of structures and mechanisms have been employed for decelerating or arresting moving objects. In particular, a number of protective barriers and energy dissipating mechanisms have been devised for arresting a moving vehicle.
At racetracks, for example, protective peripheral barrier walls (especially in the curved portions of the track) are frequently made of rigid materials such as reinforced concrete for the purpose of containing a crash vehicle in order to prevent it from deviating from the raceway and colliding with other objects, or with spectators. Such rigid walls or barriers can cause dangerous levels of deceleration (“G” forces) that may kill or severely injure the driver. Similar results may occur with these rigid barriers on public highways where serious injury or death may result when a motorist deviates from the road and collides with a rigid barrier at high velocity.
Deformable barriers have been employed in some instances to help absorb some of the energy involved in a high-speed collision. For example, “barrel” barriers, which typically consist of several crushable 50-gallon drums positioned side-by-side, provide a degree of protection to vehicles and their occupants during an impact by increasing the distance through which the vehicle is decelerated. Other examples of deformable barriers include stacked vehicle tires and bales of hay. While deformable barriers can lessen the “G” forces involved in a crash, such barriers have generally provided sub-optimal impact absorption. Moreover, deformable barriers can create problems of their own, for example, by “catching” the vehicles that strike them tangentially, leading to more severe damage and injuries than would be the case had the vehicle been permitted to skid along the barrier. In addition, if the vehicle crashes into such a barrier at high speed and is not retained by the barrier, the crashed vehicle and attendant debris can be dangerously thrown back into the path of oncoming vehicles, or into the viewing stands.
Accordingly, there is a need for an improved roadway barrier system and, more specifically, a deceleration-limiting roadway barrier system for decelerating the vehicles in a controlled manner and for retaining moving vehicles that collide with the barrier system.
Embodiments of the invention provide a roadway barrier system and method for decelerating a moving vehicle in a controlled manner and for retaining the decelerated vehicle. A net or mesh of the roadway barrier system receives and captures the moving vehicle. The net or mesh is secured to anchors by energy absorbing straps. The energy absorbing straps deploy under a tensional load to decelerate the moving vehicle, the straps providing a controlled resistance to the tensional load over a predefined displacement or stroke to bring the moving vehicle to rest. Additional features include a sacrificial panel or sheet in front of the net that holds up the net or mesh while deflecting vehicles that collide only tangentially with the roadway barrier system.
In general, in one aspect, the invention is directed to a deceleration-limiting barrier comprising a net, anchors, and a flexible strip arranged to secure the net to the anchors. Portions of the strip are joined together in a manner so as to be susceptible to being pulled apart under a load that is less than a load capacity of the strip.
In general, in another aspect, the invention is directed to a barrier for limiting decelerating of a moving body. The barrier comprises means for receiving and retaining the moving body, means for anchoring the receiving and retaining means, and means for decelerating the moving body in a controlled manner to thereby limit the deceleration thereof to below a predefined maximum deceleration level.
In general, in yet another aspect, the invention is directed to a deceleration-limiting roadway barrier system. The roadway barrier system comprises a first row of barriers positioned end-to-end alongside a roadway, and a second row of barriers positioned end-to-end alongside the first row of barriers, the barriers of the first row being staggered from the barriers of the second row. A plurality of anchors are fixedly mounted in the ground alongside the roadway. Each barrier comprises a net and one or more flexible strips arranged to secure the net to one or more anchors, with portions of each strip joined together in a manner as to be susceptible to being pulled apart under a load that is less than a load capacity of the strip.
In general, in still another aspect, the invention is directed to a method of decelerating a moving body. The method comprises receiving the moving body in a net, deploying a plurality of energy absorbing straps attached to the net, decelerating the moving body using the energy absorbing straps, and limiting the deceleration of the moving body to below a predefined maximum deceleration level.
A more complete understanding of the system and method of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein:
Following is a detailed description of the drawings wherein reference numerals for similar components and elements are carried forward.
As mentioned previously, embodiments of the invention provide a deceleration-limiting roadway barrier system and method for retaining and decelerating a moving vehicle. The roadway barrier system is designed to limit the amount of deceleration or G force experienced by the moving vehicle to a certain preset level, regardless of how fast the vehicle is traveling at the time of impact. In other words, a faster traveling vehicle will not experience more severe deceleration than a slower traveling vehicle; both vehicles will experience about the same level of deceleration regardless of their respective speeds. The specific deceleration level may be set at a certain maximum as needed to safely bring the vehicles and the occupants therein to a complete stop.
In some embodiments, the deceleration-limiting roadway barrier system comprises two parallel rows of barriers alongside a roadway or racetrack. In the description to follow, the generic term “roadway” is intended to refer both to vehicular roadways and vehicular racing tracks unless otherwise indicted. The barriers in each row are placed end-to-end along the roadway, with the barriers in one row staggered relative to the barriers in the other row. Each barrier is anchored to the ground by ground anchors and includes a net and a flexible, energy absorbing strip arranged so as to secure the net to the anchors. Portions of the flexible strip may be joined to each other in a manner such that the joined portions may be pulled apart under a load which is less than the load capacity of the strip.
Referring now to
The fasteners 14 of the loop 12 may be made of threads, cords, or other suitable fasteners, and are selected to have a lower tensile strength than that of the strap 10. The tensile strength of the fasteners 14 and, in part, the pattern in which they are stitched, determine the load required to pull apart the loop 12. It is important that this load be below the load capacity of the strap 10, preferably by at least a certain percentage. Thus, when a load is applied to the strap 10, the fasteners 14 will break or rip away to allow the loop 12 to be pulled apart. In effect, the load on the strap 10 is transferred to the fasteners 14 where it is absorbed and dissipated when the fasteners 14 break and rip away. The load capacity of the strap 10 will therefore not be reached or exceeded regardless of how large a load is applied provided there are enough fasteners 14 in the loop 12 to absorb the load.
It should be noted that, although the term “loop” is used herein, in general, any portion of the energy absorbing strap 10 may be joined to any other portion or portions of the strap 10 regardless of whether a “loop” is formed. Thus, in addition to a loop 12 being formed in the energy absorbing strap 10, a figure “S” shape, for example, or some other configuration may also be formed and stitched together in the strap 10.
The energy absorbing characteristic of the strap 10 is illustrated in
Note that, although the total absorbed load depends on both the Fr and Xm terms, the rate of absorption (i.e., how fast the load is absorbed) depends primarily on the Fr term. For purposes of the roadway barrier system of the present invention, a lower Fr translates to a more gentle deceleration, which will necessitate a larger stroke Xm, and vice versa.
Load=Fr·(Xm 1+Xm 2+Xm 3+. . . +Xmi) (2)
where the sum of Xm1, Xm2, Xm3, . . . , Xmi represent the total stroke provided by the individual loops 12 in the lanyard 30. Note that every loop 12 may have the same stroke Xm, or one or more loops 12 may have a different stroke Xm, depending on the requirements of the particular application.
In some embodiments, each loop 12 of the lanyard 30 may be designed so as to be pulled apart under the same load Fr, thereby providing the lanyard 30 with a substantially constant level of deceleration. Thus, regardless of the velocity of the vehicle (e.g., 50, 100,or 150 mph) at the time of impact with the roadway barrier system, the deceleration of the vehicle will be limited to some constant, preselected level. The higher velocity will, of course, require a longer stroke or displacement Xm to decelerate.
In other embodiments, however, one or more of the loops 12 may be designed so as to require a different (e.g., greater or lesser) load to pull these loops apart, so long as all or most of the loops can be pulled apart with a load Fr that is lower than the load capacity Fs of the lanyard 30. For example, the first loop may be designed to be pulled apart under a load Fr1 which is less than a load Fr2 required to pull apart the next loop, and so on in the series of loops. Thus, the lanyard 30 may provide a gentle deceleration initially as the weaker loops are pulled apart first, then increased deceleration as the stronger loops are pulled apart later. Such an arrangement may be useful where there is limited space available for bringing the vehicle to rest. As the vehicle approaches the end of the available space, the stronger loops can provide increased deceleration to quickly bring the vehicle to rest.
Turning now to
In some embodiments, the lanyards 30 may be connected to the net 40 via load lines 42 that are also made of a high-strength material such as Kevlar™ or Nylon™.
During assembly of the barrier 50, the lanyards 30 and the load lines 42 are folded or otherwise tucked onto the net 40, as shown, such that only the loose ends of the lanyards 30 are exposed. This assembly is then sandwiched between the front and back sacrificial panels 52 and 54 for support. The entire assembly may then be sealed, glued, or otherwise adhered together into a single barrier 50.
The assembled barrier 50 may then be attached, tied, connected, or otherwise secured via the ends of the lanyards 30 to ground anchors 60, as shown in
In some embodiments the junction 76 between two barriers 50 may be in the form of a joint such as a tongue-and-grove joint or a dovetail joint (not expressly shown). The barriers may each have male portions and female portions to facilitate the quick removal and replacement of the barriers 50. Such joints allow the barriers to simply be slid in and out of connection with other barriers. For this purpose, a supply of barriers 50 may be made readily available in a nearby storage area (e.g., a warehouse) to replace used barriers as needed.
A supporting pole, pipe, or shaft 78 made of rigid, but easily shattered material such as wood, aluminum, PVC, or other suitable material may be spaced at various points along the roadway barrier system 70 to provide vertical support the first and second rows 72 and 74, respectively, of the roadway barrier system 70. Other suitable structures such as L-shaped brackets or braces may also be used to support the first and second rows 72 and 74.
In some embodiments, the front sacrificial panel (see
While a limited number of embodiments of the invention have been described, these embodiments are not intended to limit the scope of the invention as otherwise described and claimed herein. Variations and modifications from the described embodiments exist. For example, in some embodiments, the capture net may be a sheet instead of a net. Furthermore, in some embodiments, the loops in the energy absorbing strap may be bonded, adhered, or formed using Velcro™ instead of stitches to alleviate puncturing of the strap and thereby render the strap more amenable to reuse. Accordingly, the appended claims are intended to cover all such variations and modifications as falling within the scope of the invention.
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|U.S. Classification||404/6, 244/110.00R, 49/34, 256/13.1|
|International Classification||E01F13/02, E01F13/00, E01F7/04, E01F13/12, E01F15/14, E01F15/06|
|Cooperative Classification||E01F7/045, E01F15/146, E01F13/022, E01F15/065, E01F13/12|
|European Classification||E01F15/14D2, E01F15/06B, E01F13/02B, E01F7/04B, E01F13/12|
|Feb 12, 2002||AS||Assignment|
Owner name: U.S. GOVERNMENT AS REPRESENTED BY THE ADMINISTRATO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SCHNEIDER, WILLIAM C.;LOCKE, JAMES P.;REEL/FRAME:012597/0598
Effective date: 20020108
|Sep 8, 2009||FPAY||Fee payment|
Year of fee payment: 4
|Sep 8, 2009||SULP||Surcharge for late payment|
|Sep 27, 2013||REMI||Maintenance fee reminder mailed|
|Feb 13, 2014||SULP||Surcharge for late payment|
Year of fee payment: 7
|Feb 13, 2014||FPAY||Fee payment|
Year of fee payment: 8